As those skilled in the art are aware, there are a wide variety of locking mechanisms available in the market place for door-type safes and strong boxes. Some are actuated electronically and others are based on conventional combination or key lock systems that have been used for decades. Electronic type locking mechanisms usually actuate mechanical systems that are notoriously old in the art. However, electronically actuated systems are more likely to be used with larger and more sophisticated vaults holding valuable metals like gold and silver, jewels, cash, important documents and sensitive electronic data banks. Such vaults or safes are found in banks and other businesses that require highly developed tamper proofing and break-in resistance including elaborate electronic codes and timing mechanisms. Such installations are so complicated and expensive as to be far beyond the means and/or needs of private residences, or small and medium sized businesses. Some locking mechanisms are too complicated and physically occupy too much space to be of practical use in small inexpensive safes with limited space inside.
Combination type locks and key locks are much more vulnerable to theft losses since they are not difficult to break into, damage or to penetrate by a skilled safecracker. Thus, it is well recognized that improvements in locking mechanisms are needed which increase a safe's resistance to unauthorized penetration.
The prior art of which applicant is aware includes Taiwanese Patent No. 75/210258 which shows a safe locking mechanism which combines a complex connecting linkage and a combination number lock together into an integrated structure having a spring which if worn or damaged or dislocated will render the locking device inoperative.
U.S. Pat. No. 4,926,664 to Gartner et al. shows a link 23 which is engaged by a bolt 63 and moved with an element 19 and pin 22. When the link 23 is moved the bolts 30 and 31 are extended or retracted by virtue of the slots 34 and 35 acting on pins 36 and 37.
U.S. Pat. No. 4,470,277 to Uyeda shows a similar locking mechanism with a bar 40 moving the bolts 22 in and out as the angled slots 44 act on pins 26.
None of the three references above noted resembles the instant device either structurally or in operating principles. Thus, they are of interest only.